Table I.

Kinetic parameters of PEPC of the single-cell functioning C4 species B. sinuspersici and S. aralocaspica and related chenopod species

Leaves were collected after 5 h into the light and 5 h into the dark period. Activity was assayed at pH 8.0. Values represent the mean of at least three independent determinations (ses are shown).

SpeciesPhotosynthetic TypeParameterLightDark
B. sinuspersiciSingle-cell C4Apparent Vmax (units/mg protein)1.96 ± 0.011.78 ± 0.04
Km (PEP) (mm)0.06 ± 0.010.06 ± 0.01
S. aralocaspicaSingle-cell C4Apparent Vmax (units/mg protein)1.67 ± 0.031.06 ± 0.04
Km (PEP) (mm)0.10 ± 0.010.12 ± 0.02
H. persicumKranz C4Apparent Vmax (units/mg protein)1.27 ± 0.040.87 ± 0.04
Km (PEP) (mm)0.12 ± 0.030.17 ± 0.03
S. eltonicaKranz C4Apparent Vmax (units/mg protein)0.83 ± 0.030.67 ± 0.08
Km (PEP) (mm)0.09 ± 0.020.10 ± 0.03
S. richteriKranz C4Apparent Vmax (units/mg protein)0.93 ± 0.031.00 ± 0.04
Km (PEP) (mm)0.21 ± 0.040.22 ± 0.04
S. linifoliaC3Apparent Vmax (units/mg protein)0.09 ± 0.010.08 ± 0.01
Km (PEP) (mm)0.05 ± 0.010.05 ± 0.01